Various kinds of configurations of multiplexers each transmitting packet data received from at least two cameras to an external device have been proposed (see patent related documents 1 and 2, for instance).
FIG. 5 is a block diagram that shows an instance of a conventional configuration of a multiplexer, and a multiplexer 201 has a video camera line 202 that connects with plural cameras C11, C12, C13, C14 and a video system controller 203 that connects with the video camera line 202, and is configured to transmit video signals from the respective cameras C11, . . . to a video recorder or a video display 204.